Art of cracking and coking hydrocarbons



Aug. 23, 1932. G. H. TABER,JR. ET AL 1,873,068

ART OF CRACKING AND COKING HYDROGARBONS Filed March 16, 1929 George H. Take/Jr: [mm/4 fll/mm ATTORNEYS Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE GEORGE E. TABEB, JR., OF RYE, AND EDWARD W. ISOM, OF SCARSDALE, NEW YORK, AS-

SIGNOBS TO SINCLAIR BEFINING COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE ART OF CRACKING AND COKING HYDROCAR-BONS Application filed March 16,, 1929. Serial No. 347,533.

This invention relates to improvements in the combined vapor phase cracking of Oils, such as gas oil or kerosene stocks, for the productionof lower boiling oils, such as gasoline. and the coking of heavy oils, such as crudes, topped crudes, flux oils, other residual oils and the like. This type of combined operation is of special application in the handling of crude stocks or residual stocks the handling of which usually, involvesdifliculties due to corrosion or the products of which are unusually refractory with respect to the usual refining operations, because of the character or quantity of sulphur compounds in 1 the i stock, for example, but this type of combined operation, in certain aspects, is of more general application. This invention relates more particularly to improvements in the coking operation proper in this type of'comi hined operation.

The improved coking operation of this invention is of special-value in the combined operation described in application Serial No. 340,996 filed February 18, 1929, by Harry L.

.Pelzer, which has matured into. Patent No. 1,831,719 issued November 10,1931, but it is also of more general application in this type of combined operation. v

As usually practiced, this type of combined operation involves passage of the hot vapor mixture from the vapor phase cracking operation not only through the oil stock or mixture to be reduced to coke but also through the accumulating charge of coke throughout the coking operation. As a consequence, the coke so produced is usually of lower density than the coke produced from similar stocks in the conventional coke still; -50 pounds per cubic foot as compared to 40-60 pounds per cubic foot for example. This invention provides improvements in the coking operation proper which, in this type of combined operation. make it possible materially to increase the density of the coke produced.

According to this invention, the hot vapor mixture from the vapor phase cracking operation, while still at a, high temperature, is passed in intimate contact with a liquid-oil stock or mixture to be reduced to coke in a receptacle adapted to receive an accumulating charge of coke, a vertical drum for example, and this stock is coked in this receptacle by the heat of the hot vapor mixture from the vapor phase cracking operation. and the level at which the hot vapor mixture from the vapor phase cracking operation, or at least the major part of this vapor mixture, is released within this coking receptacle is progressively elevated as the operation proceeds to maintain this level adjacent the upper surface of the charge of coke accumulating in the coking receptacle and to avoid .passing the major part of the hot vapor mixture from the "apor phase cracking operation through the accumulating charge of coke throughout the operation. a A relatively denser coke product is thus produced. This progressive elevation of the level at which the hot vapor mixture from the vapor phase cracking operation is released within the coking receptacle may be accomplished in a number of ways; two general methods are illustrated in the accompanying drawing.

The coking operation is promoted by promoting effective separation, in the coking receptacle, of vaporizable components of the stock to be reduced to coke. To this end, the oil stock to he reduced to coke is, with advantage', introduced into the coking receptacle at a level above the level at which the hot vapor mixture from the vapor phase cracking operation is released within the coking receptacle; this stock may, for example, be sprayed downwardly through a vertical drum within which the hot vapor mixture from the vapor phase cracking operation is released so that the hot vapors rise through the oil spray. \Vhen the stock to be reduced to coke is so illtroduced into the coking receptacle. a large part of the vaporizable components of the stock is separated in the space in the coking receptacle above the upper surface of the accumulating charge of coke and remaining Vaporizable components are separated from the partially coked stock as and while it forms part of the accumulating charge of coke. At least the major part of .the remaining vaporizable components are separated close to the upper surface of the accumulating charge of coke by the release of the major part of the hot vapor mixture from the vapor phase cracking operation at this level. Vaporizable components still remaining may be separated by passing a vapor or gaseous drying medi um such as steam or superheated hydrocarbon gases or vapors through the charge of coke as the operation proceeds or near'the end of the coking operation. A major part of the hot vapor mixture from the vapor phase cracking operation may be released within the coking receptacle at a progressively elevated level, in accordance with the invention, and a minor part of this hot vapor mixture released within the coking receptacle, with advantage, at a level below the level at which the major part of the hot vapor mixture is released to promote efi'ective separation of vaporizable components.

The vapor phase crackingoperation proper may be carried out, for example, as described in application Serial No. 198,621, filed June 13, 1927, by Harry L. Pelzer, and the hot vapor mixture from the digesting drums releasedwithin' the coking receptacle, or the digesting drums may be omitted and the hot vapor mixture from the heater proper released within the coking receptacle. Reference is made to this particular vapor phase cracking operation, however, solely for the purpose of illustration; the apparatus or the precise manner in which the vapor phase cracking operation is carried out is not important so long as the hot products of the operation are available to be released within the coking receptacle at temperatures upwards of 9'501050 F.

The invention will be further described in connection with the accompanying drawing which illustrates, diagrammatically and conventionally, two forms of apparatus, one in Fig. 1 and another in Fig. 2, in elevation and partly in section with parts broken away, adapted for carrying out the invention, but

fit is intended and will be understood that the invention can be carried out in other and different forms of apparatus. 7

Referring to Fig. 1, the oil stock to be reduced to coke is supplied to the coking receptacle 3 through connection 4, being released within the coking receptacle as a spray, and the hot vapor mixture from the vapor phase cracking operation is supplied to the coking receptacle through connection 17. The vapor mixture resulting from the coking operation, including components vaporized from the oil stock to be reduced to coke as well as components from the vapor phase cracking op eration, escapes through connection 18 to suitable condensing or fractionating and condensing or other recovery apparatus not shown. In carrying out the invention in this apparatus, the hot vapor mixture supplied through connection 17 is released within the coking receptacle 3 through one or more of the valved branch connections 5, 6, 7 8 and 9 connecting the manifold 10 with the coking receptacle. supplying steam to the manifold 10. Connection 12 is provided for supplying steam or other drying medium to the lower end of the coking receptacle 3. A manhead 13 is provided and the bottom 14 of the receptacle is made removable to permit discharge of the coke product and cleaning of the cokingreceptacle 3.

Referring to Fig. 2, the same parts illustrated in Fig. 1 are designated by the same reference numeral with a prime appended. In carrying out the invention in this apparatus, the hot vapor mixture supplied through connection 17 is released within the coking receptacle 3 through the free end of the swining connection 15'. The level of the free end of connection 15 is elevated or low ered by means of cable 16 extending through stufling box 19 to winch 20.

In carrying out the present invention in conjunction with the combined operation described in Patent No- 1,831,719 mentioned above, in the illustrated apparatus, the combined operation may be carried out, except for the coking operation proper, as there described.

In the apparatus illustrated in Figs. 1 and 2, the coking receptacle 3 (or 3), the hot vapor connections 17 and 18 (or 17' and 18'),

and the oil supply connection 4: (or 1') if the stock to be reduced to coke is supplied hot, are with advantage lagged or thermally insulated.

In carrying out the invention in the apparatus illustrated, for example, the hot oil vapor mixture from the vapor phase cracking operation, supplied through connection 17 (or 17) at a temperature upwards of 950- 1050 F., is passed in intimate contact with the stock to be reduced to coke, sprayed through connection l (or 4), in the coking receptacle 3 (or 3). The oil stock to bereduced to coke may be preheated, for example, to a temperature approximating 650-800 F. Initially, the hot vapor mixture supplied through connection 17 (or 17) is released within the coking receptacle at a level near the lower end of the coking receptacle. As the operation proceeds and as a charge of coke accumulates, as a result of the contact between the hot vapor mixture and the stock to be coked, tl1e level at which the hot vapor mixture, or at least the major part of the hot vapor mixture, from the vapor phase cracking operation is released within the coking receptacle is progressively elevated. In the apparatus illustrated in Fig. 1, for example, the hot vapor mixture is initially released through connection 5 and as a charge of coke accumulates the hot vapor mixture, or the major part of it, is released through connection 6, and then through connection 7, and so on. In the apparatus illustrated in Fig. 2,

Connection 11 is provided forv 'luo for example, the free end of the swinging connection 15' is initially positioned near the lower end of the coking receptacle 3' and as a'charge of coke accumulates the free end of this swinging connection is progressively ele vated. The elevation of the level at which the hot vapor mixture, or the major part of the hot vapor mixture, from the vapor phase cracking operation is released within the coking receptacle is regulated so that this level is maintained adjacent the upper surface of the charge of coke accumulating in the coking receptacle. The stock to be reduced to coke is thus passed in intimate contact with the hot vapor mixture from the vapor phase cracking operation in the upper part of the coking receptacle above the upper surface of coke is introduced, the coking operation is in terrupted, the charge of coke is discharged,

the coking receptacle is cleaned, and the coking operation is resumed.

If the coke product so produced is not as dry as desired, vaporizable components remaining in the accumulating charge of coke below the level at which the major part of the hot vapor mixture from the vapor phase cracking operation is released within the coking receptacle may be separated by introducing steam or other drying medium at a level near the lower end of the coking receptacle or at a level below the level at which the major part of the hot vapor mixture from the vapor phase cracking operation is released within the coking receptacle, or by releasing a minor part of the hot vapor mixture from the vapor phase cracking operation at a level near the lower end of the cok ing receptacle or at a level below the level at which the major part of the hot vapor mixture from the vapor phase cracking operation is released within the coking receptacle, during the coking operation, or they may be separated by introducing steam or other drying medium at a level near the lower end of the coking receptacle while the coking operation is being terminated or for a short period after it is terminated. In the apparatus illustrated in Fig. 1-,' for example, as the major part of the hot vapor mixture supplied through connection 17 is successively released through connection 6 then 7 then 8 and so on a minor part of this hot vapor mixture may continue to be released through connection or through connection 5 then 6 then 7 and so on during the operation, or a drying medium may be supplied through connection 12 during the operation, or a drying medium may be supplied through connection 12 or through connection 11 after the coking operation proper is terminated. In the apparatus illustrated in Fig. 2, for example/as the ma jor part of the hot vapor mixture supplied through connection 17' .is released at progressively higher levels through connection a minor part of this hot vapor mixture may be released through connection 12', or a drying medium may be supplied through connection 12', during the operation, or a drying medium may be supplied through connection 12 after the coking operation proper is terminated. We claim: v

1. In a combined vapor phase oil cracking and coking operation, the improvement which comprises vaporizing and cracking a hydro carbon oil in the vapor phase, introducing the hot vapor mixture from the vapor phase cracking operation into the lower portion of a coking receptacle, introducing a heavy liquid hydrocarbon oil stock to be reduced to coke into the coking receptacle, intimately admixing the hot vapor mixture and the heavy oil stock in the coking receptacle and thereby coking the heavy oil stock and causing a charge of the coke so formed to accumulate in the lower portion of the coking receptacle, and elevating the level at which at least the major portion of the hot vapor mixture from the vapor phase cracking operation is released within said receptacle to maintain this level adjacent the upper surface of the charge of coke accumulating in said receptacle as the operaton proceeds and to avoid passing the major part of said hot vapor mixture through the accumulating charge of coke throughout the operation.

2. In a combined vapor phase oil cracking and coking operation, the improvement which comprises vaporizing and cracking a hydrocarbon oil in the vapor phase, releasing the hot vapor mixture from the vapor phase cracking operation within a coking receptacle, introducing a heavy liquid hydrocarbon oil stock to be reduced to coke into said coking receptacle at a level above the level at which said hot vapor mixture is released within the coking receptacle, passing the hot vapor mixture upwardly through the coking receptacle countercurrent to and in intimate as the operation proceeds and to avoid passing the major part of said hot vapor mixture through the accumulating charge of coke throughout the operation.

5 3. In a combined vapor phase oil cracking and coking operation, the improvement which comprises vaporizing and cracking a hydrocarbon oil in the vapor phase, passing the hot vapor mixture from the vapor phase cracking operation in direct contact and intimate admixture with a heavy liquid hydrocarbon oil stock to be reduced to coke in a receptacle adapted to receive an accumulating charge of coke and thereby coking said stock in said receptacle and causing a charge of the coke so formed to accumulate in the lower portion of the coking receptacle, elevating the level at which a major part of the hot vapor mixture from the vapor phase cracking operation is released within said receptacle to maintain this level adjacent the upper surface of the charge of coke accumulating in said receptacle as the operation proceeds and to avoid passing the major part 5 of said hot vapor mixture through the accumulating charge of coke during the operation, and continuing to release a minor part of the hot vapor mixture from the va-- por phase cracking operation within said rc-' ceptacle at a level below the level at which the major part of said hot vapor mixture is released during the operation.

In testimony whereof we afli x our signatures.

GEORGE H. TABER, JR.

EDVARD W. ISOM. 

